The Queensland Government has already said it would investigate the claims.

Bowen resident and Whitsunday councillor Michael Brunker said he was "disgusted" by activists employing "before" and "after" photos as part of "a fake news campaign" to frighten people into thinking coal stockpiles were leaching into wetlands.

He said the "before" photo, taken in 2016, showed the saltpan on the 5159ha wetlands looking green and the "after" photo, taken on April 1, looking black just days after Cyclone Debbie crossed the coast between Airlie Beach and Bowen.

BELOW: Environmentalists claim these images are proof of contamination, while Whitsunday councillor Mike Brunker said the dark water is a result of fresh water mixing with salt water.

Cr Brunker said anti-mining activists claimed the dark water was caused by coal leaching into the wetlands when in fact it is rainwater on the saltpans.

"When the rainwater floods the saltpans, it becomes a dark red colour because of the salt that is in the soil," Cr Brunker said.

Adani said the satellite photographs were "misleading and not representative of the water quality in the wetland, nor is it supported by visual inspections since Cyclone Debbie''.

Cr Brunker said the Caley Valley Wetland was largely man-made.

He said in its natural form it was a salt pan, but a bund wall built 60 or more years ago to stop the intrusion of saltwater into freshwater lagoons at the southern end had meant that parts of the saltpan during periods of high rainfall became part of the freshwater lagoon.

"The water is always black in colour because freshwater, when it mixes with salt on the saltpans, goes a dark red. It looks black," he said.

Comments on the Abbot Point Action Group Facebook page yesterday showed that the group's supporters believed a spill into the wetlands had occurred.

Claudia Collingwood commented: "Horrendous! It was to be expected! Such a stupid project! They can't deny the damage now. It is so maddening!"

Jo Birtus posted: "We might get that story to UNESCO … the Great Barrier Reef is indeed in danger, of abuse by those in power!"

Cr Brunker said anti-Adani activists would go to great lengths to stop the project. "It is fake news they are spreading," he said. "People in North Queensland are sick and tired of fake rumours and accusations."

The Department of Environment and Heritage Protection said yesterday that an investigation into the incident was ongoing.

Mackay Conservation Group spokesman Peter McCallum said the images showed Adani lacked the capacity to operate in a sensitive environment.